Metal end closure



Dec. 28, 1965 c. A. HUTH 3,225,951

METAL END CLOSURE Filed Sept. 20, 1963 INVENTOR.

United States Patent 3,225,957 METAL END CLOSURE Carl Alexander Huth, Closter, N.J., assignor to American Can Company, New York, N.Y., a corporation of New Jersey Filed Sept. 20, 1963, Ser. No. 310,207 1 Claim. (Cl. 229-54) The present invention relates to a metal end closure for a tubular can and more particularly to an improved easy-opening end closure for cans containing pressureproducing or pressurized beverages such as beer, ale and carbonated beverages which are drunk directly from the can after it has been opened.

End closures of the type contemplated in the present invention include a substantially fiat, rigid lever secured to one end of a removable or tear-out area by suitable means such as a peened-over embossrnent or a rivet which is integral with the removable area. The removable area is located within the central panel of the metal can end closure and is defined by a score line out in the central panel. In order to remove the tear-out area from the can end, it is necessary merely to insert the tip of ones finger beneath the free end of the lever, and to lift the lever about the opposite end thereof adjacent its point of securement, thereby rupturing the adjacent score line. With continued pulling force exerted on the lever, gripped between the fingers, the entire removable or tear-out area is separated from the can end to permit pouring of or access to the product contained within the can. A can end embodying the above features is disclosed in the United States design patent to Fraze, 195,604, issued July 2, 1963.

Although the above described easy opening feature performs quite well and has been widely accepted by the consumer, some incidents of cut lips have been experienced when the consumer has drunk the product directly from the can by placing his mouth over the opened area in the can end. Study of this problem indicates that such cuts are caused by the relatively sharp raw metal edges on the can end which define the opening therein and which are produced when the removable area is torn from the can end along the score line therein.

A second problem in this type of can end has resulted from the formation of the score line end of the peenedover rivet which is integral with the removable area of the can end and which secures the flat lift lever to the removable area. The formation of this score line and integral rivet results in localized thinning of the metal end, and the'displaced metal is pressed outwardly from the thinned areas into the adjacent portions of the can end central panel, thereby resulting in an excess of metal in these adjacent can end portions. This excess metal causes the central panel to be deformed or bowed upwardly or outwardly a considerable distance with respect to the peripheral portion of the can end when the interior of the can is subject to the pressure exerted by the pressurized product. Because the metal end in the immediate vicinity of the score line contains the greatest proportion of excess metal and is somewhat weakened by the score line, this portion of the end experiences the greatest distortion when the end flips outwardly. This distortion of the end frequently is uneven, with the result that the end portion to which the lift tab is secured is often twisted angularly and/ or tilted upwardly so that the lift tab is caused to project upwardly beyond the upper edge of the rim of the end, in which projected position it sometimes catches upon portions of the can filling and handling equipment, thus causing jams or resulting in premature opening of the can.

The general purpose of the instant invention, therefore, is to provide a metal end closure having an easy opening feature of the type described above which is not subject to the aforementioned problems. This is accomplished by providing in the central panel of the can end a pair of raised or outwardly extending beads which are disposed closely adjacent to and on either side of the removable area in the can end, each bead extending in a generally radial direction. The beads are of a predetermined height which is sufilcient to prevent the lip of the consumer from normally contacting the relatively sharp raw metal edges which define the tear opening in the central panel of the can end.

The beads also serve to minimize and control the distortion of the end in the portion adjacent the removable area in two ways, first by drawing some of the excess metal from this portion of the can end, thus reducing the tendency of this portion of the central panel to deform or bow upwardly or outwardly; and secondly by stiffening this portion of the can end panel so that its most pronounced distortion is concentrated adjacent the inner edges of the beads, thus causing the end in the area in which the lift tab is secured thereto to bend in a reverse direction so that the free end of the lift tab is directed downwardly toward the end panel and is thus prevented from projecting upwardly along the rim of the end.

An object of the present invention, therefore, is to provide a metal end closure for a can body which may be opened by the consumer without the necessity of special tools and which, after opening, may be brought into contact with the consumers mouth for consumption of the product directly therefrom with little or no possibility of damage to the consumers lips.

Another object is to provide such an end closure wherein the raw metal edge defining the dispensing opening in the central panel of the can end is shielded to substantially prevent contact of the consumers lip therewith.

A further object is to provide such an end closure wherein the distortion of the central panel under the pressure exerted by the product is controlled to prevent the lift tab from projecting beyond the upper edge of the can.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment thereof.

Referring to the drawing:

FIGURE 1 is a plan view of a can end constructed according to the principles of the instant invention, the view showing the end prior to its attachment to a can body;

FIG. 2 is an enlarged, fragmentary, sectional view taken substantially along line 2-2 of FIGURE 1, parts being broken away;

FIG. 3 is a sectional view taken substantially along the line 44 of FIGURE 1 after the can end has been seamed onto a filled can body, the view showing the oonfiguration of the end as it is bowed outwardly by the pressure of the product therein, parts being broken away;

FIG. 4 is a sectional View, corresponding to FIG. 2, taken through the upwardly bowed end after it has been seamed onto a filled can body, parts being broken away; and

FIG. 5 is a view similar to FIG. 4, showing the can end after removal of the tear-out area therefrom, parts being broken away.

As a preferred or exemplary embodiment of the instant invention, FIG. 1 shows a can end closure generally designated 10 having a substantially flat central panel 12 surrounded by a peripheral, depressed reinforcing groove 14 which merges into a vertically extending countersink wall 16, which in turn merges with a perrpheral curled flange 18 having adhered to its underside a sealing material which forms a gasket (not shown). The end closure is adapted to be joined and hermetically sealed to a tubular can body 29 (see FIG. 3) by the well known procedure of interfolding the end flange 18 and a peripheral body flange 19 to form a conventional double seam 21, the end flange gasket (not shown) serving to provide a hermetic seal therebetween. While the end closure 10 shown in the drawing is circular in shape, it is to be understood that it may be of any suitable or desirable shape, depending on the shape of the can body. It will also be understood that the lower end of the body 20 will be suitably closed, either by an integral end, if the body be of the drawn or extruded type, or by a separate end seamed thereto, if the body be initially formed with an open bottom end.

Extending generally radially from the center of the panel 12 is a removable or tear-out area 22 completely enclosed within and defined by an endless score line 24. While the tear-out area 22 may have shapes other than that illustrated, it preferably is completely removable, that is, defined by an endless score line comprising a plurality of connected portions having a predetermined orientation and shape. Also, whatever the shape of the tear-out area 22, it is important that it have one portion where the connected score lines are relatively close together on at least three sides, for reasons to be discussed more fully hereinafter. The radially extending tear-out area 22 shown in FIG. 1 is particularly suitable for cans containmg pourable, potable beverages such as beer, ale and soft drinks such as carbonated soda which are either packed under pressure or generate their own pressure. Such beverages are herein referred to as pressurizing products.

Secured to the tear-out area 22 at its innermost end, where the parallel portions of the score line 24 are joined by an arcuate portion 25, is a substantially rigid, fiat lift tab or opening lever 26. The lever 26 is punched or cut from a strip of flat metal stock and, to increase its rigidity, there are formed therein longitudinally extending llbS or embossments 28. The lever 26 is secured at its innermost end to the tear-out area 22 by means of a peened-over embossment or rivet 29 which is integral with and drawn from the central panel 12, the rivet 29 extending upwardly through an aperture in the innermost end of the lever 26and having its upper end peened outwardly to secure the lever 26 in place. The drawing and flattening operations which create the peened-over embossment or integral rivet 29 cause a thinning of the metal in the circular portion A of the end panel 12 immediately surrounding it, and also force some of the metal which was displaced from this thinned area A to flow into the adjacent surrounding area B of the central panel 12, with the result that there is excess metal in a major portion of the central panel which causes it to be easily bowed or deformed upwardly or outwardly when the end is subjected to internal pressure. It will be understood that the thinned panel portion A lies inwardly of the broken circular line C (FIG. 1), while the portion B lies outwardly thereof.

The formation of the indented score line 24 causes the metal which is displaced by this score line to flow into the panel area D immediately surrounding the score line. Thus, this latter area D which roughly comprises the quadrant included between the radii R, R (see Fig. 1) contains the greatest amount of excess metal, and is capable of the greatest distortion when the end is flexed outwardly, as will hereinafter be seen. In addition, the score line 24 has a weakening efliect on the panel area D, which has a tendency to cause a laterally twisted or asymmetrical distortion of this panel portion D relative to the centerline of the removable area 22.

From the point of securement of the lever 26 to the tear-out area 22, and initially lying flat on the panel 12, the lever 26 extends generally along a radius different from the radius along which the removable tear-out area 22 extends. Although an infinite number of different radii can be used, including one in alignment with the radius of the tear-out area 22, it is preferred that these radii be out of alignment, and that the two radii include an obtuse angle therebetween, for reasons to be described more fully hereinafter. The outer or free end 30 of the lever 26 is upturned slightly away from the adjacent panel 12, thereby allowing the fingertip of the consumer to be readily inserted under the free end 30 of the lever 26 for the purpose of opening the container, which procedure will be explained hereinafter.

Closely adjacent and parellel to the parallel portions and the diverging portions of the endless score line 24, there are formed in the central panel 12 a pair of generally symmetrical, upwardly extending or raised beads or projections 32 and 34 (FIGS. 1 and 2). The beads 32 and 34 are of a predetermined height (preferably at least .035 inch above the top of the panel 12) which is sufficient both to shield the adjacent raw metal edges of the central panel 12 when the tear-out area 22 is removed therefrom, and to draw a predetermined or substantial amount of the excess metal from the central panel portion D along the radial portions of the score line 24 outwardly of the tear-out area 22 to thereby reduce the tendency of the panel portion D in that area to bow or to deform upwardly or outwardly and to impart rigidity to the panel portion D to substantially eliminate its asymmetrical distortion. The beads 32 and 34, therefore, serve a two-fold purpose, namely, to shield the adjacent raw metal edges at the score line 24 when the tear-out area 22 is removed from the central panel 12, and to control the distortion of the central panel portion D.

When the end closure 10 is secured to a filled can body containing a pressurising product P such as beer, ale or carbonated soda, the central panel 12 which contains the excess of metal is bowed or bulged upwardly under the influence of the internal pressure of the product P (see FIGS. 3 and 4). While the beads 32, 34 do draw some of the excess of metal from the panel in the portion D around the removable area 22, they do not take it all, and thus this portion of the panel bows upwardly to a greater degree than do the other portions of the panel.

However, as stated, the beads 32, 34 also stiffen and reinforce the end panel, and thereby control the distortion of the portion D by causing the removable area 22 to flex symmetrically upwardly in a more or less straight line (see FIG. 3) and to then bend sharply in a reverse direction at or adjacent to the line C so that the thinned circular portion A containing the rivet 29 is reversely inclined downward therefrom in such a manner that the lift tab 24 is also inclined downwardly and thus is prevented from projecting upwardly beyond the upper edge of the double seam 21.

To open a sealed container of the type illustrated, the consumer first inserts a tip of the finger or fingernail under the upturned free end 30 of the lift lever 26 and lifts upwardly. Upon continued lifting of the free end 30, the lever 26 fulcrums around its opposite end adjacent its point of securement to the tear-out area 22. Because of the obtuse angular relationship between the lever 26 and the tear-out area 22, this fulcruming exerts a combination lifting-twisting stress on the portion of the score line 24 closely adjacent the point of securement, which results in a ready rupturing of this portion of the score line 24 and initial opening of the container.

It has been found that a substantially greater rupturing force is necessary if the score line 24 is spaced, too great a distance from the point of securernent of the lever 26. Pulling of the lever 26 with the now separated inner portion of the tear-out area 22 attached thereto easily tears through the remainder of the score line 24, thereby resulting in complete removal of the tear-out area 22 from the central panel 12. The release of internal pressure causes the panel 12 to tend to reassume its original flattened shape, as shown in FIG. 5.

As also shown in FIG. 5, after the tear-out area 22 is removed from the central panel 12, the opening 36 in the central panel is defined by the raw metal edges 38 of the panel 12. The beads 32 and 34 are of a height suffioient to prevent the lip (indicated by the numeral 40) of the consumer from contacting the raw metal edges 38 when the end closure 10 is brought to the mouth of the consumer, for consumption of the product therein.

It is obvious that, without departing from the scope of the instant invention, the beads 32, 34 could be used with any type of metal end closure having an easy opening feature embodying a tear-out area defined by a score line such that raw metal edges result in the end closure upon removal of the tear-out area therefrom.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

A tearable metal end closure for a container having a pressurized product therein, comprising a circular recessed central panel enclosed within an upstanding end wall, a removable section within said panel enclosed by an endless score line and extending generally along a first radius of said panel, a substantially rigid lift lever having one end secured to the inner end of said removable section adjacent said score line by an integral rivet formed in said section at the center of said central panel, said lift lever extending generally along a second radius which is disposed at an obtuse angle to said first radius, the metal of a substantially circular portion of said. central panel surrounding said rivet being thinner than the adjacent surrounding annular portion of said panel, a pair of generally radially extending beads disposed in said annular panel portion on opposite sides of said removable section to shield the raw metal edges of said score line when said removable section is torn from said panel, the inner ends of said beads terminating adjacent said thinner panel portion, said beads reinforcing the immediately adjacent area of said annular panel portion to cause said area and said removable section to symmetrically deform radially inwardly and upwardly in a generally straight plane when said central panel is bowed upwardly by the pressure within the container, said symmetrical deformation of said reinforced panel area causing said thinner panel portion and said lift lever to be inclined radially downwardly relative to said reinforced panel area to insure that the free end of said lift lever will be disposed beneath the upper edge of said upstanding end wall when said panel is bowed upwardly.

References Gited by the Examiner UNITED STATES PATENTS D. 195,604 7/1963 Fraze 220--54 201,939 4/1878 Nolty 22053 2,112,231 3/1938 Speidel 220--54 FOREIGN PATENTS 27,062 12/ 1902 Great Britain.

THERON E. CONDON, Primary Examiner.

GEORGE O. RALSON, Examiner. 

